[PATCH v2 05/13] riscv: cpufeature: extend riscv_cpufeature_patch_func to all ISA extensions

From: Jisheng Zhang <jszhang@kernel.org>
To: Palmer Dabbelt <palmer@dabbelt.com>,
	Paul Walmsley <paul.walmsley@sifive.com>,
	Albert Ou <aou@eecs.berkeley.edu>,
	Anup Patel <anup@brainfault.org>,
	Atish Patra <atishp@atishpatra.org>,
	Heiko Stuebner <heiko@sntech.de>,
	Andrew Jones <ajones@ventanamicro.com>
Cc: linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
	kvm@vger.kernel.org, kvm-riscv@lists.infradead.org
Subject: [PATCH v2 05/13] riscv: cpufeature: extend riscv_cpufeature_patch_func to all ISA extensions
Date: Mon,  5 Dec 2022 01:46:24 +0800	[thread overview]
Message-ID: <20221204174632.3677-6-jszhang@kernel.org> (raw)
In-Reply-To: <20221204174632.3677-1-jszhang@kernel.org>

make the riscv_cpufeature_patch_func() scan all ISA extensions rather
than limited feature macros.

Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Heiko Stuebner <heiko@sntech.de>
---
 arch/riscv/include/asm/errata_list.h |  9 ++--
 arch/riscv/kernel/cpufeature.c       | 73 +++++-----------------------
 2 files changed, 15 insertions(+), 67 deletions(-)

diff --git a/arch/riscv/include/asm/errata_list.h b/arch/riscv/include/asm/errata_list.h
index 19a771085781..722525f4fc96 100644
--- a/arch/riscv/include/asm/errata_list.h
+++ b/arch/riscv/include/asm/errata_list.h
@@ -6,6 +6,7 @@
 #define ASM_ERRATA_LIST_H
 
 #include <asm/alternative.h>
+#include <asm/hwcap.h>
 #include <asm/vendorid_list.h>
 
 #ifdef CONFIG_ERRATA_SIFIVE
@@ -20,10 +21,6 @@
 #define	ERRATA_THEAD_NUMBER 2
 #endif
 
-#define	CPUFEATURE_SVPBMT 0
-#define	CPUFEATURE_ZICBOM 1
-#define	CPUFEATURE_NUMBER 2
-
 #ifdef __ASSEMBLY__
 
 #define ALT_INSN_FAULT(x)						\
@@ -53,7 +50,7 @@ asm(ALTERNATIVE("sfence.vma %0", "sfence.vma", SIFIVE_VENDOR_ID,	\
 #define ALT_SVPBMT(_val, prot)						\
 asm(ALTERNATIVE_2("li %0, 0\t\nnop",					\
 		  "li %0, %1\t\nslli %0,%0,%3", 0,			\
-			CPUFEATURE_SVPBMT, CONFIG_RISCV_ISA_SVPBMT,	\
+			RISCV_ISA_EXT_SVPBMT, CONFIG_RISCV_ISA_SVPBMT,	\
 		  "li %0, %2\t\nslli %0,%0,%4", THEAD_VENDOR_ID,	\
 			ERRATA_THEAD_PBMT, CONFIG_ERRATA_THEAD_PBMT)	\
 		: "=r"(_val)						\
@@ -127,7 +124,7 @@ asm volatile(ALTERNATIVE_2(						\
 	"add a0, a0, %0\n\t"						\
 	"2:\n\t"							\
 	"bltu a0, %2, 3b\n\t"						\
-	"nop", 0, CPUFEATURE_ZICBOM, CONFIG_RISCV_ISA_ZICBOM,		\
+	"nop", 0, RISCV_ISA_EXT_ZICBOM, CONFIG_RISCV_ISA_ZICBOM,	\
 	"mv a0, %1\n\t"							\
 	"j 2f\n\t"							\
 	"3:\n\t"							\
diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
index a4d2af67e05c..6244be5cd94a 100644
--- a/arch/riscv/kernel/cpufeature.c
+++ b/arch/riscv/kernel/cpufeature.c
@@ -252,58 +252,11 @@ void __init riscv_fill_hwcap(void)
 }
 
 #ifdef CONFIG_RISCV_ALTERNATIVE
-static bool __init_or_module cpufeature_probe_svpbmt(unsigned int stage)
-{
-	if (!IS_ENABLED(CONFIG_RISCV_ISA_SVPBMT))
-		return false;
-
-	if (stage == RISCV_ALTERNATIVES_EARLY_BOOT)
-		return false;
-
-	return riscv_isa_extension_available(NULL, SVPBMT);
-}
-
-static bool __init_or_module cpufeature_probe_zicbom(unsigned int stage)
-{
-	if (!IS_ENABLED(CONFIG_RISCV_ISA_ZICBOM))
-		return false;
-
-	if (stage == RISCV_ALTERNATIVES_EARLY_BOOT)
-		return false;
-
-	if (!riscv_isa_extension_available(NULL, ZICBOM))
-		return false;
-
-	return true;
-}
-
-/*
- * Probe presence of individual extensions.
- *
- * This code may also be executed before kernel relocation, so we cannot use
- * addresses generated by the address-of operator as they won't be valid in
- * this context.
- */
-static u32 __init_or_module cpufeature_probe(unsigned int stage)
-{
-	u32 cpu_req_feature = 0;
-
-	if (cpufeature_probe_svpbmt(stage))
-		cpu_req_feature |= BIT(CPUFEATURE_SVPBMT);
-
-	if (cpufeature_probe_zicbom(stage))
-		cpu_req_feature |= BIT(CPUFEATURE_ZICBOM);
-
-	return cpu_req_feature;
-}
-
 void __init_or_module riscv_cpufeature_patch_func(struct alt_entry *begin,
 						  struct alt_entry *end,
 						  unsigned int stage)
 {
-	u32 cpu_req_feature = cpufeature_probe(stage);
 	struct alt_entry *alt;
-	u32 tmp;
 
 	if (stage == RISCV_ALTERNATIVES_EARLY_BOOT)
 		return;
@@ -311,25 +264,23 @@ void __init_or_module riscv_cpufeature_patch_func(struct alt_entry *begin,
 	for (alt = begin; alt < end; alt++) {
 		if (alt->vendor_id != 0)
 			continue;
-		if (alt->errata_id >= CPUFEATURE_NUMBER) {
-			WARN(1, "This feature id:%d is not in kernel cpufeature list",
+		if (alt->errata_id >= RISCV_ISA_EXT_MAX) {
+			WARN(1, "This extension id:%d is not in ISA extension list",
 				alt->errata_id);
 			continue;
 		}
 
-		tmp = (1U << alt->errata_id);
-		if (cpu_req_feature & tmp) {
-			/* do the basic patching */
-			patch_text_nosync(alt->old_ptr, alt->alt_ptr,
-					  alt->alt_len);
+		if (!__riscv_isa_extension_available(NULL, alt->errata_id))
+			continue;
 
-			riscv_alternative_fix_auipc_jalr(alt->old_ptr,
-							 alt->alt_len,
-							 alt->old_ptr - alt->alt_ptr);
-			riscv_alternative_fix_jal(alt->old_ptr,
-						  alt->alt_len,
-						  alt->old_ptr - alt->alt_ptr);
-		}
+		/* do the basic patching */
+		patch_text_nosync(alt->old_ptr, alt->alt_ptr, alt->alt_len);
+		riscv_alternative_fix_auipc_jalr(alt->old_ptr,
+						 alt->alt_len,
+						 alt->old_ptr - alt->alt_ptr);
+		riscv_alternative_fix_jal(alt->old_ptr,
+					  alt->alt_len,
+					  alt->old_ptr - alt->alt_ptr);
 	}
 }
 #endif
-- 
2.37.2

